One of the most disturbing facets of modern office life is the flashing light on the copy machine which signals that it is time to replace the toner. This can be a messy task, and, in some machines, downright difficult. It goes without saying that the longer the system can run without a need to change the toner, the more efficient the system will be.
In situations where high volume unattended service is necessary, such as, for example, automatic ticket printing machines, it is critical that the time between service calls be maintained at a high level. This is difficult to achieve because, in addition to the toner, there is developer which must be changed periodically. In the systems where toner is added from a container by the user, the developer and toner are combined into a monocomponent material. However, this type of system reduces the print quality. Because of the magnetic nature of the developer, there is no convenient method of adding developer without replacing the entire developer/toner cartridge.
Another source of maintenance is the electrostatic rotating drum upon which the image is formed by the toner adhering to the charged spots of the drum. It is this toner which is transferred to the paper stock to form the reproduced image on the stock. The drum must be cleaned after each rotation and eventually the drum retains enough residual toner to blur the transferred image. When this happens the drum must be cleaned by hand. This then is a maintenance activity that could be time consuming and not easily accomplished by an untrained operator.
The image which is presented to the drum is created in an image unit which uses modulated light, or which creates modulated light, such as for example the exposure module shown in the aforementioned Patent Application titled Printing System Exposure Module Optic Structure and Method of Operation. Such exposure modules can have alignment problems, electrical problems, and, or course, light source failure problems.
A still further source of periodic maintenance is the fuser which operates to set the transferred toner to the paper so that the image is permanently bonded to the paper. The fuser is a sophisticated set of pressure rollers which can build up deposits and smudge the paper. Also, the roller can wear, thereby changing pressure on the stock and causing intermittent bonding.
In a typical automatic ticket machine the requirements are at least five to ten times longer for proper operation.
A typical office printing machine will typically print less than 20,000 pages while a ticket printer is required to print 40,000 coupons per month. The toner alone must last for a minimum of 50,000 coupons.
A need therefore exists in the art for a xerographic printer which allows for a high number of reproductions to occur before requiring toner/developer changing or drum or fuser cleaning or replacement.
A further need exists for such a printer which allows for the simple replacement of toner/developer while still maintaining high quality and which allows for the easy replacement of the electrostatic drum or fuser.